1. Field of the Invention
The present invention, in general, relates to a bowl cutter knife for use with the knife head of a bowl cutter machine and, more particularly, to a bowl cutter knife of the kind having a substantially convexly curved cutting edge.
2. The Prior Art
Curved bowl cutter knives are well-known for cutting or chopping sausage meat and the like. At one end, the blade of such knives with their convexly curved cutting edge is provided with a tang or other suitable means for mounting it on a rotary knife shaft of a bowl cutter machine.
So-called bowl cutter machines are used for the production of sausage meat and the like. They consist of a rotary bowl of suitable capacity for receiving the meat and of a knife head attached to a rotary knife shaft. The knives of the rotary knife head are aligned relative to the internal wall or walls of the bowl such that they may chop and mix the meat within the bowl. Conventionally, the knives are driven at speeds up to 5,000 r.p.m. While the position of the knife is substantially stationary, the bowl and the contents therein rotate relative to the knives whereby the contents are continuously moved against the knives as the bowl is rotating.
The essential aspects of the cutting operation are the cutting action itself and the emulsifying action of the knife blades, whereby the raw material is usually emulsified with water. To this end, a predetermined quantity of ice and/or water is added to the sausage dough within the bowl which is then worked into the dough by the rotating knives in order to yield a sausage dough of as uniform a granular consistency and homogeneity or appearance as possible. In addition to providing as great a cutting efficiency as possible, it is important to produce a stable emulsion. In the event, the cutting blades exert a certain amount of friction upon the meat particles which leads to the generation of considerable heat. The heat developed during the cutting operation may rise significantly and lead to knife surface temperatures as high as 100.degree. C. However, the denaturation temperature of protein is about 40.degree. C. Consequently, thin films of the sausage dough may denature at or on the cutting blades and diffuse or penetrate into the sausage dough.
In order to limit the development of heat as much as possible during the cutting process, knives of various structures have been used. Thus, German patent 4,214,730 C2 discloses a cutter knife provided at its lateral surfaces with grooves and undulations extending arcuately with a radius substantially the same as the radius of the cutting blade. The grooves and undulations on the lateral surfaces of the knife are intended not to affect the emulsifying action in the emulsification zone. Frictional heat is intended to be reduced by the arrangement and disposition of the grooves and undulations, and the purpose of the concentric disposition of the undulations and grooves is to prevent a jagged cutting edge as a result of regrinding the cutting edge.
Another cutter knife is known from German patent 4,339,496. The knife is structured to provide a longitudinally extending channel at the rear edge of the blade, the channel being connected to a fluid conduit provided in the knife mounting chuck and provided with a fluid outlet at the rear margin of the blade. Water flowing in the channel is intended to cool the knife surface for reducing the temperature in the vicinity of the operation. This cutter knife is also convexly curved and is provided with a forwardly disposed cutting edge, i.e. in the direction of rotation, the rear edge of the knife being of concave configuration. The mentioned channel is provided in the concave edge.
The hitherto known cutter knives suffer from the drawback of the meat to be cut engaging, or adhering to, the entire lateral surfaces of the cutter knife, thus forming a certain sausage dough film thereon which detrimentally affects the cutting process and results in denaturization of the meat.
Prior publications, such as German patents 421,512; 629,843 and 676,550 disclose cutter knives provided with openings in their lateral surfaces. The openings are structured to provide additional cutting edges and to influence the kneading of the meat to be chopped.
The innovation disclosed by German utility model 1,802,811 relates to a cutter knife for a meat cutter. In the vicinity of its cutting portion the knife is provided with a slot-like notch extending substantially parallel to the cutting edge which is intended to function as an additional cutting edge.
These solutions aim at increasing the number of cutting edges of the disclosed cutter knives and at bringing about partially improved kneading of the masses to be chopped. They do, however, affect the diminution process and the quality of the material to be chopped in an extremely detrimental manner which in the final analysis also has a negative influence on the thermal load of the sausage dough.